Chapter 2: General Information
Bolt Torque Specifications
What You Should Know
It takes more force to tighten a 3/4'' bolt than to tighten a 1/2'' bolt because of its larger diameter. It also
takes more force to tighten a grade 8 bolt than it does to tighten a grade 5 bolt because of the greater
material strength. A bolt that is waxed or otherwise lubricated requires much less force to tighten. If the
same amount of force is used with a lubricated bolt as with a non-lubricated bolt, the lubricated bolt often
will break.
CAUTION
Under no condition shall any other fasteners be substituted for those supplied by
the manufacturer.
Table 2-2 Recommended initial tightening torque
Size
Grade #5 Assembly Torque Grade #8 Assembly Torque
Dry
Lubricated
Dry
Lubricated
1/4"-20 8 ft. lbs. 75 in lbs. 12 ft. lbs. 9 ft. lbs.
1/4"-28 10 ft. lbs. 86 in lbs. 14 ft. lbs. 10 ft. lbs.
5/16"-18 17 ft. lbs. 13 ft. lbs. 25 ft. lbs. 18 ft. lbs.
5/16"-24 19 ft. lbs. 14 ft. lbs. 25 ft. lbs. 20 ft. lbs.
3/8"-16 30 ft. lbs. 23 ft. lbs. 45 ft. lbs. 35 ft. lbs.
3/8"-24 35 ft. lbs. 25 ft. lbs. 50 ft. lbs. 35 ft. lbs.
1/2"-13 75 ft. lbs. 55 ft. lbs. 110 ft. lbs. 80 ft. lbs.
1/2"-20 90 ft. lbs. 65 ft. lbs. 120 ft. lbs. 90 ft. lbs.
5/8"-11 150 ft. lbs. 110 ft. lbs. 220 ft. lbs. 170 ft. lbs.
5/8"-18 180 ft. lbs. 130 ft. lbs. 240 ft. lbs. 180 ft. lbs.
3/4"-10 260 ft. lbs. 200 ft. lbs. 380 ft. lbs. 280 ft. lbs.
3/4"-16 300 ft. lbs. 220 ft. lbs. 420 ft. lbs. 320 ft. lbs.
7/8"-9 320 ft. lbs. 320 ft. lbs. 600 ft. lbs. 460 ft. lbs.
1"-8 640 ft. lbs. 480 ft. lbs. 900 ft. lbs. 680 ft. lbs.
1-1/8" - 7 800 ft. lbs. 600 ft. lbs. 1280 ft. lbs. 960 ft. lbs.
1-1/4" - 7 1120 ft. lbs. 840 ft. lbs. 1820 ft. lbs. 1360 ft. lbs.
1-3/8" - 6 1460 ft. lbs. 1100 ft. lbs. 2380 ft. lbs. 1780 ft. lbs.
1-1/2" - 6 1910 ft. lbs. 1460 ft. lbs. 3160 ft. lbs. 2360 ft. lbs.
Table 2-3 Proof load and strength details
Bolt Diameter
Medium Carbon Steel, Quenched and Tempered
Carbon Alloy Steel, Quenched and
Tempered
Proof Load
Yield Strength Tensile Strength
Proof Load
Yield Strength Tensile Strength
1/4" to 3/4" 85000 92000 120000 120000 130000 150000
3/4" to 1-1/2" 74000 81000 105000
Grade 5 bolts are designated by three slash marks on the head.
Grade 8 bolts are designated by six slash marks, evenly spaced on the head of the bolt.
14
PNEG-2308 Chain Loop Power Sweep
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